The sound of silence

March 24, 2013
 by Paul McGowan

Yesterday’s post sparked a number of comments and observations and one that came to the forefront was the ability of the subwoofer to help with a sense of space – not just hitting lower bass notes. We all recognize a sub’s ability to produce the lowest notes of a piano or organ, T-Rex stomping and earthquakes, but space?

By sense of space I am referring to a phenomena many of us may have not experienced or, if we have, may not have recognized what is going on.

In the first few seconds of some recordings, especially older analog recordings, the mastering engineer allows some lead in space where the musicians are not playing but you hear the intrinsic background “silence” that isn’t, in fact, so silent. In this space you can hear the rumbling of air conditioners, the movement of the air in the room, perhaps the shuffling of musicians, tape hiss or any number of artifacts of the room or the space it was recorded in.

This gives you a sense of the room, the size, the environment – a baseline if you will – of the space in which it was recorded. Your ear/brain instinctively adjusts to that background level as the baseline and then everything else recorded comes out of this fabric. It is amazing how live and real this type of recording can be – but without a proper subwoofer setup in the room you will never be able to experience this.

I remember the first time I realized what was going on was during a listen to the Cowboy Junkies album Trinity Sessions, recorded in a church in Toronto using a single stereo microphone in a live setting. The opening few seconds of the first track, Mining for Gold, has a few seconds of this room noise before Margo Timmins begins to sing. On a lesser system you hear some background noise that’s apparently just an artifact of the engineer turning up the level to capture her performance; reducing in level quickly after her solo.

On a proper system, however, you immediately hear the space of the Trinity Church, the size of the room, the air around her and you’re drawn into that space and become a part of that space. Once inside you discover that the rumble is clearly an air conditioning unit off in the background and as you listen into the space even deeper, you can actually hear the tiny “squeak, squeak, squeak” of a bad bearing in the air conditioner’s fan – way off in the distance. Now, when Timmins begins to sing, you hear and appreciate her in the actual space she was recorded in. What’s happened is the sounds now make sense to you, perhaps for the first time. Instead of just an annoying rumble, the puzzle is decoded and you not only understand the space it was recorded in but you become a part of that space. That is something I cannot be without.

The first few times I listened to that track I had a subwoofer in the setup, but it was a single POS setup poorly. At the time I didn’t know enough about subwoofers; their importance and their role in a system to make it work. To be honest, I had a sub for two reasons: I was an Audiophile and Audiophiles had subs, and I like bass. Two poor excuses for adding anything into a setup.

My friend, mentor and future partner in business, Arnie Nudell, was the first to show me what it was all about. Arnie and his partner in Infinity, Carrie Christy, were pioneers in bringing the category of subwoofers into audio in the first place – having built and marketed one of the very first subwoofers for home audio in their classic Servo Statik loudspeakers in 1966 – while I was still in high school.

So, sorry, we were going to get rolling on setup but I thought this point important enough to make in today’s post.

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15 comments on “The sound of silence”

  1. People can’t miss what they’ve never had – but the sense of “you are there” is, in my book, the very thing that separates an audiophile system from a great hi-fi.

  2. Hi Paul-
    I’m relatively new to your postings and they have refreshed past knowledge and brought new. If I may backtrack to your posting “Sub Woofer.” One line stood out where you say that if your speakers are not flat from 40Hz, then don’t consider a subwoofer, but replace your speakers. Looking back through many issues of Stereophile for speaker reviews, I found very few that were flat from 40Hz and those that were cost $15,000 on up. Looking at the frequency graphs showed that most did not go “flat” until 90-100Hz and were down 1-5db at 40. What am I missing since $15-188,000 are way out of my budget.
    You also touched on the need for careful placement of the subwoofer and crossover point. Would appreciate if you would expand your commentary here, since I have 2 quite different “powered” subs and have never really been able to integrate them properly with the main speakers.
    Thanks again… I look forward to your daily postings.

  3. This whole concept is so new to me, it leaves me gasping for air. So let me see if I understand this correctly. It never entered my mind to listen to recordings this way. To summarize your listening method if I’ve got it right, you listen to the lead in before the music hoping the mikes are at normal gain and sense infrasonic vibrations as well as near infrasonic sounds at very low frequencies produced by subwoofers from coincidental pickup of room rumble from air conditioning systems, subway trains, and any other extraneous sounds like street traffic, construction equipment that gets on the recording. These sounds have no specific directional origin in the room but their reflections within the room give you audible cues which you listen to intently to judge the size and shape of the space. Then you try to fix this in your mind as you integrate it with the sounds of the musicians whose reflections reach the microphone but much attenuated by comparison. By keeping this sense of space in your mind, you integrate that with the recording of the music and manage to mentally combine the two. This can be further reinforced in pauses in the music when these extraneous sounds become predominant again and at the end of the recording when the mikes hopefully remain open before the recording ends. And this is how high end audio equipment conveys the acoustic sense of space? Did I get it right? I’ll have to try it and see how it works.

    But this isn’t how sounds producing a sense of space is actually heard in a live performance in a large venue. It’s the reflections of the musical sounds themselves we hear that conveys the space. It happens at every frequency. It happens all the time. It doesn’t require intense concentration to hear it, it’s inescapable. Isn’t that what a high fidelity electronic music reproducing system is supposed to do? What would a system that could do that successfully be worth? It certainly wouldn’t sound anything like what you described if I understand it right.

    1. Ah, if only I were as well thought out and eloquently stated as yourself I might be able to help – but I am not. Perhaps the reasoning is all wrong, so don’t get hung up on that. Give the track I suggested from the Trinity sessions a go and see what you think – perhaps there’s another explanation. What I can tell you is that the added realism is there on these recordings, for whatever reason.

  4. You want 18″ subwoofers, build your own. Here’s a good one that’s not too expensive for hobbyists;

    I think it’s reasonable to expect PE will offer a kit with this driver, enclosure, high powered plate amp, stuffing and whatever else is needed for a finished product. Question, how much bass and to what LF cutoff do you actually want or need? This of course depends on the size and acoustics of your room.

    BTW Floyd Toole who has done considerable research related to room acoustics and uniformity of bass response recommends 4 subwoofers. There’s a detailed explanation on Harman International’s web site about how to optimize bass response. For some reason, audiophiles have completely ignored his advice.

      1. That may be so, I wouldn’t know. I haven’t shopped for high fidelity loudspeakers for around 40 years but I manage to acquire them when they keep falling out of the sky on me. I was going to listen to Snell Ultima Salon a few months ago just out of curiosity because I’d read an article where John Atkinson seemed to love them so much. I wanted to find out what about them he was raving over. But I never got around to it. I think it was designed by Voecks who had a hand in Snell. This was at JBL’s high end Northridge Ca facility owned of course by Harman International. Interesting what people’s opinions of loudspeakers are especially considering how many of them are on the market. One era’s best in the world is another era’s “oh that old junk.” Even at the same time there’s a very wide range of opinions of the same equipment. That’s when I acquire them, when nobody wants them anymore and people practically give them away. I figure out what’s wrong with them and decide if the design can be salvaged. It’s a lot cheaper and much more fun that way.

        Once upon a time when DIYers whether basement tinkerers or kit builders were a larger segment of the market and prices were rational this was a hobby that seemed like much more fun. Hard to reconcile audio equipment costing as much as a house being taken seriously, at least not by me.

        Now if you don’t want to build an 18″ subwoofer yourself using the Dayton driver, Harman has a new one for you already built. It costs a mere $20,0000 a pop. If you take Toole’s advice and buy four of them it will set you back only $80,0000. Of course if you buy those IRS Vs and take his advice you’ll need two extra bass towers 🙂

        So what is Harman telling its customers with these $20,000 subwoofers, you won’t get enough bass from your $20,000 Revel Salon Ultimas or your $50,000 K2s. K2 looks to me like a reworked version of the JBL Hartsfield. It’s another one of those that has a response to about 40 or 50 kHz. I’m glad I’m not an audiophile anymore.

      1. If you read the second review you’ll find this;

        Outdoor ground plane measurements by an independent third party testing yeilded positive performance results. Of note, the the published xmax (12.75m) appears to be relatively conservative. One can expect to reach ~20mm xmax before non-linearity becomes an issue. These subs are clearly underrated. Source:

        You also have to take into context the fact that 1/2 inch Xmax for an 18″ woofer moves considerably more air than 1/2″ for a 12″ woofer. Allowing a generous 3″ for the surround would give an effective surface radiating area of 36 pi squre inches compared to 16 pi for an AR 12″. Do you think a pair of these in 5 cubic foot sealed enclosures critically damped with a pair of 1000 watt plate amplifiers could damage the structure of your house? 🙂

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